Additional dependency:

Fast Chunk Pregenerator

https://www.spigotmc.org/resources/fast-chunk-pregenerator.74429/

• It is used by default when using the /anb create command. You can manually regenerate the world with another plugin after using the /anb create command. The world to generate "NextBlock_Reference".

How to start:

• /anb create

It will create two worlds. 1 is empty for the game. 1 pre-generated will be used to transfer blocks from it to the first world. (admin command)

• /anb join

(player command)

Info:

A small game location will be generated for the Player and he will receive an infinite block to generate 1 layer (1x1).
You can create games with large sizes (3x3), (5x5), (9.9)... /and give "nick" "gen_type"

Gif